With the continuous development of display technologies and the public needs, mobile electronic devices, such as mobile phones, tablets, etc., are becoming more and more popular in people's daily lives. Their functions increase and are more widely used. By observing the market of mobile electronic devices in recent years, it can be seen that the high screen-to-body ratio is an irresistible trend. In addition, compared to the existing electronic devices, the electronic devices with a high screen-to-body ratio have advantages including a larger display area, a narrower frame, a smaller dimension with the same size screen size, and so on. However, there are some necessary functional elements, such as a camera, an infra-red sensor, an iris camera, an earpiece, etc., on the front panel of the electronic device. Accordingly, the display screen of the current electronic device needs to conceal these elements. Full-screen display cannot be achieved.